1. Field of the Invention
The present invention relates generally to coronary catheters. In particular, the present invention is a catheter for use in connection with medical procedures on the left coronary artery.
2. Description of the Related Art
Catheters used in connection with medical procedures on the coronary system are generally known and disclosed, for example, in the following U.S. patents, all of which are hereby incorporated by reference in their entirety and for all purposes:
______________________________________ Inventor U.S. Pat. No. ______________________________________ Ruiz 4,973,306 Ruiz 4,735,620 Bower 5,299,574 Rickerd 5,322,509 Voda 5,401,258 ______________________________________
Coronary catheters of the type described in the above-identified patents typically include an elongated and flexible tubular member mounted to a hub. The tubular member includes a relatively long and generally straight section sometimes referred to as the body stock which extends from the hub, and a nonlinear or curved section sometimes referred to as the stem which extends from the body stock. The distal end of the stem is often terminated with a tip.
The size, flexibility and other characteristics of catheters will vary depending upon their intended use. One particular type of catheter used for catheterization of the left coronary artery is known as a left coronary catheter. Left coronary catheters are inserted tip first into the femoral, brachial or radial artery of the patient and directed upwardly through the aorta until the tip is positioned adjacent to and engaged with the ostium or opening of the left coronary artery. During this catheterization procedure the tip of the catheter passes in sequence through the descending aorta, the aortic arch and the ascending aorta. Once it has been inserted, the catheter can be used for a wide variety of medical procedures. By way of example, interventional devices such as stents, rotational and directional atherectomy devices, guidewires and other devices can be deployed to the left coronary artery through the lumen in the catheter. Catheters of this type can also be used to guide and support balloon dilation catheters for percutaneous transluminal coronary angioplasty (PTCA) or percutaneous transluminal peripheral angioplasty (PTA), and for injecting dyes and other contrast media into the artery in connection with these procedures.
To be efficacious, left coronary catheters must be capable of being quickly inserted and removed from the aorta. The catheters must also be capable of accurately positioning their tips at the ostium of the artery being treated, without suddenly extending into and damaging the artery, a characteristic known as diving. The catheter also must provide a back-up support since after it is inserted, a force known as the deployment force will be exerted on the interventional device being directed to the artery through the catheter. Without sufficient back-up support insertion of an interventional device may not be possible and trauma to the body vessels or ostium may occur. It is desirable that the inserted catheter be capable of retaining its position to allow the interventional device to be accurately deployed within the artery, even if relatively high deployment force is required. The catheter should, of course, be capable of providing these characteristics and properties while avoiding damage to the body vessels through which it is directed.
The shape of the catheter stem is an important factor contributing to the overall success of the procedures described above. Decisions on whether a given device can be delivered to a treatment site and the procedure successfully performed often depend upon the ability to appropriately catheterize the patient. There is, therefore, a continuing need for catheters having improved stem shapes.